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HomeMy WebLinkAboutObservation of Excavation 05.02.2023 5020 County Road 154 Glenwood Springs, CO 81601 phone: (970) 945-7988 fax: (970) 945-8454 email: kaglenwood@kumarusa.com www.kumarusa.com Office Locations: Denver (HQ), Parker, Colorado Springs, Fort Collins, Glenwood Springs, and Summit County, Colorado May 2, 2023 Russell Cartwright 35 Willowview way Parachute, Colorado 81635 russecart@gmail.com Project No. 21-7-229.21 Subject: Observation of Excavation, Proposed Residence, Lot 2, Block 1, The Fairways, Battlement Mesa, 21 Hogan Circle, Garfield County, Colorado Dear Russell: As requested, a representative of Kumar & Associates observed the excavation at the subject site on April 24, 2023 to evaluate the soils exposed for foundation support. The findings of our observations and recommendations are presented in this report. The services are supplemental to our agreement for professional services to you dated March 1, 2021. We previously conducted a subsoil study for design of foundations at the site and presented our findings in a report dated July 21, 2021, Project No. 21-7-229. The proposed construction is similar to that discussed in our report and will consist of a single-story wood frame structure over crawlspace. Spread footings bearing on the natural soils sized using an allowable bearing pressure of 1,500 psf were designed for foundation support based on the recommendations in our previous report. At the time of our site visit, the foundation excavation which was nearly complete had been cut in one level from nil to about 4 feet below the adjacent ground surface. The soils exposed in the bottom of the excavation consisted of stiff, sandy silt. Results of swell-consolidation testing performed on samples taken from the site, shown on Figure 1, indicate the soils are moderately to moderately high compressible under conditions of loading and wetting with a moderate hydro- compression potential. The sample may have been partly disturbed due to the sampling process. No groundwater was encountered in the excavation and the soils were slightly moist. The soil conditions exposed in the excavation are generally consistent with those previously encountered on the site and suitable for support of spread footings designed for the recommended allowable bearing pressure of 1,500 psf. There is some risk of settlement if the bearing soils were to become wetted and precautions should be taken to prevent wetting. Loose and disturbed soils should be removed in the footing areas to expose the undisturbed natural soils and the subgrade compacted. Other recommendations presented in our previous report which are applicable should also be observed. The recommendations submitted in this letter are based on our observation of the soils exposed within the foundation excavation and the previous subsurface exploration at the site. Variations Kumar & Associates